Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove PCB from fan assembly (For instructions click HERE)

Measurement:

Test 1:
Measure the resistance across the fan
motor terminals on the left hand side.
Resistance should be approximately 60 Ohms.
Test 2:
Measure the resistance from either of the fan motor terminals to a suitable earth point.
Resistance should be greater than 1M Ohm.
(OL is acceptable because it is greater than 1Mohm)
Test 3:
Check that the fan spindle turns freely and that there is no sign of damage or water ingress in the fan.
Note:
Instructions supplied with fan PCB may suggest a 2nd resistance test, this test is unnecessary and the resistance given is wrong.